Overhauls Go Further Than The Engine

When most aircraft owners think of overhaul, they think about their engine. And, that's a justified train of thought. The two largest engine manufacturers in general aviation make a good deal of fuss concerning their TBO numbers, and many owners have found them to be fairly accurate.

Being a company that focuses on aircraft engines, however, we've noticed over the past few days here in our office that it seems as though our articles, and customer correspondence has been becoming a little to "engine heavy." And, as Al Mooney would iterate during his retirement: he would rather talk about something other than airplanes because that's all he's talked about his whole life, let's talk about something other than the engine. Let's talk about your propeller.

If it wasn't for the fine folks at AOPA, EAA, and other owner groups who slave late into the night writing far better articles than ours, I suspect many aircraft owners wouldn't even know that their propeller, like their engine, has a published TBO. And, just like their engine, propellers can only be overhauled only so many times before they need to be sent to the scrap yard.

Many propeller manufacturers spare us of a lot of pain, and have made propeller TBOs about equal to engine TBOs (Check your maintenance manual for more detailed information). So, if you're taking your engine off for an overhaul, it is also probably time to send your propeller in, too. And yes, that means you fixed pitched folks as well. Your local A&P IA likely won't have the appropriate tools and expertise on how to overhaul a propeller, so you'll likely have to send it to a specialized shop, or back to the manufacturer to get work done. These shops will look at things (for a fixed pitch prop) like pitch, track, shape, amount of material left, balance, and micro-crack progression. Rest assured they will help you through the process, and let you know if something will prevent your propeller from surviving another couple thousand hours in the field.

As an owner, it can seem like a passive process. Remove the prop, ship it to the shop, pay the money, bolt it back on. But, this is a critical time to be aware of what you're doing, and to look at your operational profile over the past few years to see what your next steps are. Are a lot of your trips into short fields and traveling short distances? Well, maybe it's time to swap your cruise prop for a climb prop. Talk to your A&P and propeller shop about different propeller types for your airplane. Manufacturers usually allow owners to use several different pitches, and a couple different lengths. It is up to you to determine (with professional advice, of course) what combination of engine and prop best serves you.

As always, we recommend getting your prop balanced on your aircraft. Almost all shops have the ability to do it, and it is not an expensive or time consuming procedure. The results, however, are noticeable. And, if you're going through the process of putting a fresh engine in your bird, you owe it to your airframe to make the ride as smooth as possible. All the Gemco employees have their prop balanced at each annual, and no one reports feeling like they wasted their money. 

This article doesn't serve to be comprehensive. More, we hope it serves as a subtle reminder to owners and operators that their prop undergoes some serious stress in day-to-day operations. Forgetting to maintain your prop might be a short term gain, but will be a long term loss when something goes wrong. So pay attention to your prop, and enjoy the ride.

Dylan Grimm